Rac-2-Oxotricyclo2.2.1.0.sup.3,5 !heptane-7-carboxylic acid is accessible starting from norbornadiene by the Prins reaction and a subsequent Jones oxidation, and is an important precursor for the preparation of prostaglandins (Bindra, Grodski, Schaaf, Coney, J. Am. Chem. Soc. 1973, 95, 7522; Cervinka, Habartova, Coll. Czech. Chem. Comm. 1983, 48, 3565; Bartmann, Beck, Jahne, Lerch, Wess, Liebigs Ann. Chem. 1987, 321; CS 240,862).
It has been known for over twenty years that the resolution of rac-2-oxotricyclo2.2.1.0.sup.3,5 !heptane-7-carboxylic acid can be effected with the aid of (S)-(-)-phenylethylamine, by preparation and multiple recrystallization of the phenethylammonium salt (Bindra, Grodski, Schaaf, Corey, J. Am. Chem. Soc. 1973, 95, 7522; Bartmann, Beck, Jahne, Lerch, Wess, Liebigs Ann. Chem. 1987, 321; CS 240,862). This process is very laborious and unacceptable on the industrial scale for economic reasons.